package list;

public class PersonDemo {
    public static void method2(StringBuilder sBuilder){
        sBuilder.append("A");
        sBuilder.append("B");
        System.out.println(sBuilder.toString());
    }

    //我们在main操作一下
    public static void main(String[] args){
        StringBuilder s = new StringBuilder();

        new Thread(()->{
            s.append("a");
            s.append("b");
        }).start();

        method2(s);



    }

}
